During operation textile machines involved in fiber preparation such as cards generate considerable amounts of dust, fibers, and lint which are emitted at various points on the card as the stock proceeds through the machine. Various lickerin and doffer waste collection plenums or hoods are disclosed in the prior art which are mounted on the upper portions of the machine and connected to suction ducts leading to filtration systems, and are generally adequate to capture most of the dust and fibers emitted upwardly from the upper portions of the card machine.
Cleaning of the undercard chamber or cavity has been a more difficult task to perform due to the size thereof and the turbulence generated by the rotation of the elements thereabove. Efforts have been made to eliminate dust and lint in such an area which, at the outset amounted to manual, periodic shoveling or scraping of accumulated lint from beneath the machine by workers. Subsequently plenums with attached suctions ducts have been installed under the carding elements to capture lint, dust and fly that fall through. Examples of such prior art devices include the British Pat. to David Walsh No. 562,740 in which an undercard cleaning system is provided with a collection tube or suction opening at one end of the chamber and a fan at the other end thereof which blows air currents toward the collection tube. Other examples of undercard cleaning systems are illustrated in the United States Pat. to Schonenberger No. 2,964,804 and to Gunter No. 4,057,877. Both of these patents are illustrative of collection plenums or tubes which are designed to continuously clean the underneath area of the carding machine. A further example of pneumatic cleaning of the chamber beneath the carding elements of a textile machine is illustrated in applicant's co-pending application Ser. No. 961,936 filed Nov. 20, 1978.
While each of these systems is effective to automatically eliminate a considerable portion of the lint, dust and fly beneath the carding machine there remain several unsolved problems which severly limit the efficiency of these vacuum or pneumatic cleaning systems. First of all most undercard floor surfaces are not smooth enough for the waste to be moved across it with gentle air currents. Secondly, there are various areas beneath a carding machine which contain sharp edges or burrs to which pieces of lint attach themselves and grow as time goes by. These pieces of lint are called tags and are caused by rough edges. Further, most carding machines are provided with a cross-girt which is an underneath brace for the frame of a carding machine and which amounts to a hump or protuberance extending transversely across the floor beneath the carding machine at about the midpoint thereof. Lint being blown or sucked from one end to the other encounters this obstruction and accumulates on the upstream side thereof. Such accumulations are very difficult to remove merely by pneumatic means. Also, one of the problems with existing pneumatic means is the many stray currents of air in the area beneath the carding machine caused by cracks or openings. Most carding machines are provided with a frame which has small pedestals or feet beneath the sides. In levelling the card, shims are placed beneath the feet which even increase the size of existing cracks between the floor or surface on which the card is mounted and the lower edge of the frame. Such cracks adversely or deleteriously affect the efficiency of a pneumatic undercard cleaning system.